That informal language is undignified…
A fundraising appeal is not a business letter. Say it again. Keep saying it until you believe it. An appeal should read like a letter from a dear friend. Or better yet, like a phone call from that friend, transcribed.
So yes, there will be contractions, because people use contractions when they speak. (Listen to yourself next time and note how often you do.) Yes, there will be incomplete sentences. And ellipses… and – dashes.
There will be sentences that begin with a conjunction. And all of it is perfectly OK. Because (see how I did that?) this appeal shouldn’t sound like business correspondence. It should sound like a heartfelt request you are making of a kind person.
If you have ever had to defend your appeal letter, Mary Mcahalane has put together a list of the most common complaints. Share it with the colleague who wants to change your appeal simply because she doesn’t like it. Or the board member who would NEVER respond to something like this.
The thing is, your colleagues or you don’t have to like what works. But you’ll do what works if you want to raise money.
Here are the complaints Mary sees most often:
https://mcahalane.com/why-the-things-you-hate-make-good-appeals/